1. Field of the Invention
The present invention relates generally to a display device, and more particularly to a display device comprising a plurality of self-luminous elements.
2. Description of the Related Art
In recent years, organic electroluminescence (EL) display devices have attracted special attention. Since the organic EL display device is a display device including self-luminous elements, it has such features as a wide viewing angle, small thickness without a need for backlight, low power consumption, and a high responsivity speed.
For these features, the organic EL display device is a promising candidate for the next-generation plat-panel display device, which will take the place of liquid crystal display devices. The organic EL display device includes an array substrate. The array substrate is configured such that a plurality of organic EL elements are arranged in a matrix as self-luminous elements. Each organic EL element has such a structure that an organic active layer with a light-emitting function is sandwiched between an anode and a cathode.
If the organic EL element comes in contact with moisture or oxygen in outside air, its light-emission characteristics would deteriorate very quickly. To avoid this, various techniques have been proposed to shield the major surface of an array substrate, on which organic EL elements are disposed, from outside air, thus sealing this major surface. As an example of such techniques, a sealing technique has been disclosed, wherein an organic film and an inorganic film are stacked on an electrode that is disposed on the top surface side of the organic EL element (see, e.g. Yuji Yanagi, “For Realization of Mass-Production of Thin, Large, Flexible Substrates”, Flat Panel Display 2003, NIKKEI BP, Dec. 27, 2002, pp. 264-270). As another example, a sealing technique has been disclosed, wherein a plurality of barrier layers of inorganic material are stacked and an upper barrier layer covers an underlying barrier layer (see Jpn. Pat. Appln. KOKAI Publication No. 2003-217829).
When the above-described techniques are used, it is important to effectively suppress infiltration of moisture or oxygen from an end face of a protection layer that seals an organic EL element.